shell for being willing to cooperate on getting to the science. but as i told marvin before we stepped out onstage, in colorado, you know, just repeatedly now, shell has been there calling for stronger regulations of its own industry, agreeing with e.d.f. on how to go forward in a way that really is very meritorious. so i just want to thank you, marvin, for what shell is doing on this topic. [applause] >> you mentioned the -- that there would need to be a mix of energy. you mentioned nuclear. is there a danger that the extraordinary growth of unconventional gas and oil in america creates a sense of abundance and no longer a need to worry about renewables that marvin talked about, and nuclear, for example? >> it's certainly having an impact on investment and research and development, there's no question about it. it has slowed down. we were something like 17 nuclear reactors being considered just to keep us at 20%. nuclear is 20% of our world power mix today and that's backed off. we have four being built in the country. but you see that happening. the thing we have to worry about, agai